Powdered green tea, especially Matcha is effective in maintaining beauty and health because it enables ingestion of not only water soluble substances but also all insoluble components (lipid soluble vitamin, mineral, etc.), that is, abundant function components such as various vitamins, catechin (tannin), caffeine, amino acid, dietary fiber, and micro-mineral, and also has low calorie. Thus, owing to rising concern about beauty and health in recent years, drinking Matcha creates a boom.
Conventionally, consumers drink Matcha by putting an appropriate amount of Matcha in a tea cup, pouring hot water therein, quickly mixing Matcha in the hot water using a tea stirrer. In this case, consumers can more easily drink Matcha if it is easily dissolved in hot water or cold water without using the tea stirrer. In addition, it is assumed that if the dispersibility of Matcha is enhanced, the absorptance of ingredients of Matcha into the body is accelerated so that physiological activity of the body is enhanced.
However, when consumers try to dissolve Matcha in hot water or cold water without using the tea stirrer, they cannot dissolve it completely, and lumps of Matcha not dissolved may float in the water. The Matcha not completely dissolved in the water is not pleasant to the taste and tastes gritty when consumers drink it.
In recent years, many consumers take in health food and Chinese herbal medicine in order to maintain beauty and health. Consumers drink some powdered health food and powdered Chinese herbal medicine by dissolving them in cold water. In this case, just like Matcha, the powder is not completely dissolved and lumps of the powder not dissolved float in the water, and the powder not completely dissolved in the water is not pleasant to the taste when consumers drink it. Thus it becomes difficult to drink the powdered health food and the powdered Chinese herbal medicine.
In this case, the particle size of Matcha, the powdered health food and the powdered Chinese herbal medicine is not uniform, and according to fine analysis, it is found that each of those powdery substances is a mixture of fine grained particles (for example, average particle diameter is smaller than or equal to 10 μm) and slightly large particles (for example, average particle diameter is 10 to 60 μm). The fine grained particles have advantages in that the absorptance to the body is satisfactory, the precipitation after being dispersed in water is suppressed, and they can be easily re-dispersed even if precipitation occurs, and they taste pleasant and are soft and pleasant on the tongue, whereas the large particles have advantages in that the wetness is satisfactory and the dispersibility is satisfactory.
Thus, if an appropriate dry classification apparatus for classifying powdery substances according to the size is provided, by employing the classification apparatus and performing classification, it is possible to produce a mixture made from only particles of a size within a constant range or a mixture including particles of different sizes by a constant fraction, whereby it is possible to produce the poedery substance which easily disperses into cold water without forming a lump, the powdery substance which rarely precipitates once dispersed, and the powdery substance which is soft and pleasant to the taste and on the tongue during drinking.
In the prior art, there exists a method of classifying the powdery substances according to the size by sieving, but a dry classification apparatus for easily and efficiently classifying the powdery substance according to the size does not exist.